rawConversion {base} | R Documentation |
Conversion and manipulation of objects of type "raw"
.
charToRaw(x) rawToChar(x, multiple = FALSE) rawShift(x, n) rawToBits(x) intToBits(x) packBits(x, type = c("raw", "integer"))
x |
object to be converted or shifted. |
multiple |
logical: should the conversion be to a single character string or multiple individual characters? |
n |
the number of bits to shift. Positive numbers shift right
and negative numbers shift left: allowed values are |
type |
the result type, partially matched. |
packBits
accepts raw, integer or logical inputs, the last two
without any NAs.
Note that ‘bytes’ are not necessarily the same as characters, e.g. in UTF-8 locales.
charToRaw
converts a length-one character string to raw bytes.
It does so without taking into account any declared encoding (see
Encoding
).
rawToChar
converts raw bytes either to a single character
string or a character vector of single bytes (with ""
for
0
). (Note that a single character string could contain
embedded nuls; only trailing nulls are allowed and will be removed.)
In either case it is possible to create a result which is invalid in a
multibyte locale, e.g. one using UTF-8. Long vectors are
allowed if multiple
is true.
rawShift(x, n)
shift the bits in x
by n
positions
to the right, see the argument n
, above.
rawToBits
returns a raw vector of 8 times the length of a raw
vector with entries 0 or 1. intToBits
returns a raw vector
of 32 times the length of an integer vector with entries 0 or 1.
(Non-integral numeric values are truncated to integers.) In
both cases the unpacking is least-significant bit first.
packBits
packs its input (using only the lowest bit for raw or
integer vectors) least-significant bit first to a raw or integer vector.
x <- "A test string" (y <- charToRaw(x)) is.vector(y) # TRUE rawToChar(y) rawToChar(y, multiple = TRUE) (xx <- c(y, charToRaw("&"), charToRaw("more"))) rawToChar(xx) rawShift(y, 1) rawShift(y, -2) rawToBits(y) showBits <- function(r) stats::symnum(as.logical(rawToBits(r))) z <- as.raw(5) z ; showBits(z) showBits(rawShift(z, 1)) # shift to right showBits(rawShift(z, 2)) showBits(z) showBits(rawShift(z, -1)) # shift to left showBits(rawShift(z, -2)) # .. showBits(rawShift(z, -3)) # shifted off entirely